Mixtures of pigments

Abstract

The invention relates to a mixture of at least two different pigments of the formula ##STR1## with the difference lying in the meanings of the radicals A and B, in which the formula (I) A and B are the same or different alkyl, aralkyl, cycloalkyl, carbocyclic or heterocyclic aromatic radicals, which mixture of pigments is obtainable by (a) reacting 1 mole of a disuccinate with 1.75 to 1.998 moles of a nitrile of the formula ACN and 0.002 to 0.25 mole of a nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A, or (b) reacting 1 mole of a lactam of formula (II) or of an enamine of formula (III) ##STR2## in which formula each of R and R' independently of the other is alkyl or aryl, with 0.75 to 0.998 mole of a nitrile of the formula ACN and 0.25 to 0.002 mole of a nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A, in an organic solvent, in the presence of a strong base and at elevated temperature, and subsequently hydrolyzing the resultant reaction product. The mixture of pigments is suitable for coloring material of high molecular weight, in particular plastics and lacquers, in red shades of excellent fastness properties.

What is claimed is: 
     
       1. A mixture of pigments containing at least two different pigments of formula (I) ##STR8## with the difference lying in the meanings of the radicals A and B, in which formula (I) A and B are the same or different alkyl, aralkyl, cycloalkyl, carbocyclic or heterocyclic aromatic radicals, which mixture of pigments is obtainable by (a) reacting in a molar ratio 1 mole of a disuccinate with 1.75 to 1.998 moles of a nitrile of the formula ACN and 0.002 to 0.25 mole of a nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A, or   (b) reacting in a molar ratio 1 mole of a lactam of formula (II) or of an enamine of formula (III) ##STR9##  in which formulae each of R and R' independently of the other is alkyl or aryl, with 0.75 to 0.998 mole of a nitrile of the formula ACN and 0.25 to 0.002 mole of a nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A, in an organic solvent, in the presence of a strong base and at elevated temperature, and subsequently hydrolysing the resultant reaction product.   
     
     
       2. A mixture of pigments according to claim 1, obtainable by using per mole of a disuccinate or of the lactam of formula (II) or of the enamine of formula (III) 1.8 to 1.99 or 0.8 to 0.99 moles of the nitrile of the formula ACN and 0.01 to 0.2 mole of the nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A. 
     
     
       3. A mixture of pigments according to claim 1, obtainable by using per mole of a disuccinate or of the lactam of formula (II) or of the enamine of formula (III) 1.9 to 1.98 or 0.9 to 0.98 moles of the nitrile of the formula ACN and 0.02 to 0.1 mole of the nitrile of the formula BCN or of a mixture of several nitriles of the formula BCN, the radicals B of which are different from A. 
     
     
       4. A mixture of pigments according to claim 1, obtainable by using a homogeneous nitrile BCN. 
     
     
       5. A mixture of pigments according to claim 1, obtainable by starting from nitriles of the formulae ACN and BCN, wherein A and B are carbocyclic or heterocyclic aromatic radicals. 
     
     
       6. A mixture of pigments according to claim 1, obtainable by starting from nitriles of the formulae ACN and BCN, wherein A and B are radicals of the formula ##STR10## which differ with respect to their chemical properties and/or the position of the substituents X, Y and Z, in which formula each of X, Y and Z independently is hydrogen, halogen, carbamoyl, cyano, trifluoromethyl, C 2  -C 13  alkylcarbamoyl, C 1  -C 12  alkyl, C 1  -C 12  alkoxy, C 1  -C 12  alkylmercapto, C 2  -C 13  alkoxycarbonyl, C 2  -C 13  alkanoylamino, C 1  -C 12  monoalkylamino, C 2  -C 24  dialkylamino, or is phenoxy, phenylmercapto, phenoxycarbonyl, phenylcarbamoyl or benzoylamino, each unsubstituted or substituted by halogen, C 1  -C 12  alkyl or C 1  -C 12  alkoxy. 
     
     
       7. A mixture of pigments according to claim 6, wherein at least one of the substituents X, Y and Z is hydrogen. 
     
     
       8. A mixture of pigments according to claim 1, obtainable by starting from nitriles of the formulae ACN and BCN, wherein A and B are radicals of the formula ##STR11## which differ with respect to their chemical properties and/or the position of the substituents X 1  and Y 1 , in which formula each of the substituents X 1  and Y 1  independently of the other is chlorine, bromine, C 1  -C 4  alkyl, cyano, C 1  -C 4  alkoxy, phenoxy which is unsubstituted or substituted by chlorine or methyl, or is carbamoyl, C 2  -C 5  alkylcarbamoyl, or phenylcarbamoyl which is unsubstituted or substituted by chlorine, methyl or methoxy. 
     
     
       9. A mixture of pigments according to claim 8, wherein one of the substituents X 1  and Y 1  is hydrogen. 
     
     
       10. A mixture of pigments according to claim 1, obtainable by starting from nitriles of the formulae ACN and BCN, wherein A and B are radicals of the formula ##STR12## in which formulae X 2  is methyl, isobutyl, chlorine, bromine, methoxy, phenoxy or cyano, X 3  is methyl, chlorine or cyano and X 4  is methyl or chlorine, or wherein A or B is a β-pyridyl or γ-pyridyl radical. 
     
     
       11. A mixture of pigments according to claim 1, obtainable by starting from nitriles, wherein A is the phenyl, 4-chlorophenyl or 4-biphenylyl radical and B is the phenyl, 3-chlorophenyl, 4-chlorophenyl, 4-methylphenyl, 4-isobutylphenyl, 4-bisphenylyl or 3-cyanophenyl radical. 
     
     
       12. A mixture of pigments according to claim 1, obtainable by using benzonitrile as the nitrile of the formula ACN and p-chlorobenzonitrile as the nitrile of the formula BCN. 
     
     
       13. A mixture of pigments according to claim 1, obtainable by using p-chlorobenzonitrile as the nitrile of the formula ACN and isophthalonitrile as the nitrile of the formula BCN. 
     
     
       14. A mixture of pigments according to claim 1, obtainable by using p-chlorobenzonitrile as the nitrile of the formula ACN and 4-cyanobiphenyl as the nitrile of the formula BCN. 
     
     
       15. A mixture of pigments according to claim 1, obtainable by using p-chlorobenzonitrile as the nitrile of the formula ACN and 4-cyanopyridine as the nitrile of the formula BCN.